WO 2006/005736 describes a coffee-making machine having a delivery assembly including an injector, for injecting hot water under pressure into a cartridge, and an infusion chamber, for receiving the cartridge and for release of the liquid product, where the injector and the chamber are coaxial to a horizontal axis of the assembly, with the chamber that is movable with respect to the injector. The cartridge is introduced into the delivery assembly from above, by means of a loading arrangement that comprises an upper inlet duct, underneath which means for retention of the cartridge are operative. The aforesaid retention means are constituted by a stationary gripper device, which includes two symmetrically opposite jaws, set transverse to the aforesaid horizontal axis in an area comprised between the chamber and the injector. The jaws are hinged, at the respective upper ends, to pins parallel to the aforesaid axis in order to swing between a condition of retention and a condition of release of the cartridge, against the action of a spring. The jaws are shaped so as to define between them an upper funnel-shaped housing and a substantially cylindrical lower seat, coaxial to the aforesaid axis.
In use, a cartridge is inserted in the inlet duct, until it enters the aforesaid funnel-shaped housing, and then pushed with an energy sufficient to cause divarication of the jaws, with the consequent passage of the cartridge into the underlying cylindrical seat, where the cartridge is withheld by the jaws by means of the action of the corresponding springs. Next, the infusion chamber, in the course of its own advance towards the injector, engages the bottom part of the jaws, causing divarication thereof and thus making possible passage of the cartridge within the chamber.
After the step of preparation and dispensing of the liquid product, the chamber moves back towards its initial position so as to enable reclosing of the jaws on the exhausted cartridge. The exhausted cartridge is in this way extracted from the chamber and again withheld between the jaws at the end of cycle. Next, when a user introduces into the inlet duct a new cartridge, the thrust exerted downwards on the latter causes divarication of the jaws, thereby enabling dropping of the exhausted cartridge towards a discharge passage of the assembly.
In the solution described in WO 2006/005736, the stationary gripper device including the jaws is relatively cumbersome. Supply of the cartridges is relatively inconvenient in so far as it requires the user to exert a push downwards, such as to cause divarication of the jaws. A substantial disadvantage of this type of solution is represented by the fact that removal from the assembly of an exhausted cartridge implies that in the assembly itself a new cartridge is inserted. The solution hence proves disadvantageous from the hygienic standpoint, in particular when the machine is not used for a certain period of time. Within an exhausted cartridge there remain in fact both the substance used for the infusion and residue of water, which with the passage of time can give rise to bad odours or to moulds.
In order to overcome said drawback, delivery assemblies have been proposed in which the means for retention of the cartridge are configured for performing also a function of extraction of the exhausted cartridge from the infusion chamber, in the course of a movement of recession between the injector device and the infusion chamber.
For example, EP-A-2046170 describes a delivery assembly in which the infusion chamber can be translated linearly with respect to the injector, and the latter laterally supports two opposite jaws, which are able to assume a closed position and an open position. When the injector is in a position spaced from the chamber, the jaws are forced elastically into a closed condition in order to be able to receive in a purposely provided seat thereof a peripheral flange of the cartridge, and thus support the cartridge itself. Next, in the course of advance of the chamber towards the injector, a front inclined surface of the jaws interacts with an inclined surface defined in the body of the injector in such a way as to cause divarication of the jaws, and thus disengagement of the cartridge from the aforesaid seat, when the cartridge is already partially introduced into the infusion chamber. After dispensing of the beverage, recession of the infusion chamber with respect to the injector brings about reclosing of the jaws, with a purposely provided extraction portion of said jaws that comes to engage the flange of the cartridge. In this way, in the course of the aforesaid recession, the reclosed jaws determine extraction of the cartridge from the infusion chamber, with the cartridge that can drop by gravity into the discharge passage of the assembly.
Solutions of the same type as the one described in EP-A-2046170, albeit constituting an improvement from the hygienic standpoint as compared to the more traditional known art, are, however, relatively cumbersome and imply—at each dispensing cycle—a significant mechanical interference between the jaws and the injector, with consequent wear of the components and possible misalignments.
Said drawbacks are partially overcome in solutions of the type as the one described in EP-A-2077087, on which the preamble of Claim 1 is based. This document regards a delivery assembly wherein a movable injector has two shafts projecting laterally, each of which is loosely engaged in a slot of a respective lateral jaw, with each jaw that is supported in a movable way by a respective guide member fixed with respect to the stationary structure of the assembly. In this way, the displacement of the injector also brings about displacement of the jaws supported by the corresponding guide members. The jaws are shaped for supporting the cartridge laterally and at the bottom, after this has been inserted from above into the assembly, and each of them has a front peg and a rear peg, substantially perpendicular to the shafts that constrain the jaws themselves to the injector.
As has been said, fixed laterally to the stationary structure of the assembly are two guide members of the jaws. Each guide member comprises a pair of components set on top of one another and in parallel positions, operatively set between which is the respective jaw. The two aforesaid components each have a shaped groove, which defines a substantially closed cam path, engaged in which are the front pin and the rear pin of the respective jaw.
Also in this solution, in the position where the chamber and the injector are set at a distance apart, the jaws are in a closed position or close to one another, to receive and support the cartridge. The cam path has a forward stretch configured in such a way that, in the course of approach of the injector to the chamber, the jaws open only after the cartridge has been almost completely inserted in the infusion chamber. After dispensing of the liquid product, in the course of recession of the injector, the jaws reclose, and a spring inside the infusion chamber forces the cartridge to come out of the chamber, with the cartridge that is supported by a bottom portion of the jaws, purposely shaped. In the course of recession of the injector, the front pin of each jaw is forced to engage a return stretch of the cam paths, which, at a certain point, brings about divarication of the jaws so as to enable dropping of the cartridge by gravity into the discharge passage of the assembly. Solutions of this type are also described in CN-A-101073470 and CN-Y-201044719.
Consequently, in this solution, in the course of a dispensing cycle, the jaws pass twice from a closed, or retention, condition to an open, or release, condition and precisely a first time practically at the end of advance of the injector towards the infusion chamber, and a second time in the course of recession of the injector towards the starting position. At the moment of the first opening, the cartridge is almost completely inserted into the infusion chamber, whereas upon second opening the cartridge is free to drop by gravity into the discharge passage of the assembly. Said function is allowed by the presence of cam paths of a substantially closed or non-reversible type, i.e., devised in such a way that the front pins of the jaws describe, in the course of recession of the injector from the infusion chamber, a stretch of path different from the one that they had followed in the course of approach of the injector to the chamber.
Also in this type of solutions, the system with jaws is cumbersome and constructionally complicated, in view of the need to envisage the aforesaid non-reversible cam paths, defined in the corresponding components that support the jaws. Said jaws are relatively cumbersome, on account of their particular conformation. The system is moreover potentially subject to jamming.